A gas turbine generally includes, in serial flow order, a compressor section, a combustion section and a turbine section. During operation, air enters the compressor via an inlet system and is progressively compressed as it is routed towards a compressor discharge or diffuser casing. The compressed air is routed into individual combustors of the combustion section. At least a portion of the compressed air is mixed with a fuel and burned within a corresponding combustion chamber defined within each combustor, thereby generating high temperature and high pressure combustion gases.
Liquid fuel may be supplied to the combustors from a fuel supply skid or system via various pipes, conduits, valves and tube fittings. During installation and/or over time, fuel leaks may be present or develop around the fittings. One known method for detecting fuel leaks is to pressurize the fuel circuit with the fuel or an inert gas such as nitrogen at a full working pressure which is typically from about 500 psig or greater. Although effective, this leak detection process has a few drawbacks. For example, one drawback is that the current process is time intensive. More specifically, in order to complete this detection process the tubes routed to each combustor or combustion can has to be disconnected upstream from a corresponding check valve or 3-way valve and tested separately before being reconnected. The primary reason for this is that the check or 3-way valves are configured to open at about 100 psig. As a result, if the tubes were connected the fuel circuit would depressurize when the pressure exceed 100 psig, thereby causing a loss of test pressure. This may also mean that the final connection at the check or 3-way vales cannot be verified in the test. In addition, testing at 500 psig and above, especially with compressible fluid, may require special safety considerations for technicians.
Accordingly, there is a need to provide an improved method or process for detecting leaks in a fuel circuit of a gas turbine. More particularly, there is a need to provide a method for detecting fuel system fitting or fluid coupling leaks for a gas turbine combustor with the ability to leave the corresponding tubes or conduits in situ.